ifconfig --CKO

[baiju_3]

Hi ,
From one server I can't reach my backup network , there was a * on netstat -in o/p for that i/f . I made it down configured it back it still not working , checked linkloop is also not responding .

Is there any significance of CKO as displayed in ifconfig o/p ?

lan4: flags=1843
inet 10.10.10.59 netmask fffff800 broadcast 10.10.15.255

Thanks for your reply,
baiju.

[Jeff_Traigle · Accepted solution]

CKO is the checksum-offload option. Haven't seen it before... just found it with a quick Yahoo! search.

As for your interface not working, if linkloop isn't working either, then you have a cabling or NIC problem. That indicates a failure at the physical layer. If that's not working, the higher levels of the network stack won't work either.

[Steven E. Protter]

Shaloim baiju,

I would tend to think there is a physical problem with your network, or your lan adapter.

As a standard check, I'd at least run mstm/cstm/xstm (your choice) diagnostics to see that the hardware is solid.

I'd check the link lights and port configuration on the network switch.

SEP

[Jeff Schussele]

Remember one must linkloop to another MAC in the *same* subnet. You can't linkloop from your backup net to your public net.

And don't discount the switch port as the offender. Here, we see about a 3 - 1 ratio where the switch port was the problem - not the NIC or cable.

My $0.02,
Jeff

[Sameer_Nirmal]

Hi,

CKO is Checksum offload. It is a host assistance feature provided by Network Interface Cards (NICs).
A NIC with CKO feature accelerates checksum generation and verification by performing this function for the host CPU, thus offloading the checksum operations off the CPU.
Hence CPU intervention for network operations is reduced and it is quite useful feature.
For NIC which supports this feature, CKO would be displayed in "ifconfig"

Is the interface still showing * after configuring it?
You need to ensure the route/getway etc to reach from your network to backup network.

[baiju_3]

Thanks.

[rick jones]

Might be better to say that linkloop needs to be to another system in the same broadcast domain rather than subnet. Those reading subnet may infer that is IP subnet when in point of fact linkloop doesn't care about IP so doesn't care about the IP subnet.

Also, apart from MPE, I think HP-UX is the only OS that has driver support for the frame sent by linkloop. There is a freshmeat project that provides a linkloop command and response server for Linux:

http://freshmeat.net/projects/linkloop/

if folks try it and like it they should start asking their favorite distro's to include it.